A Gas is said to be

- Boyle's law
- Charles law
- Avogadro's law
- Daltons law

In the mid 1600's, **Robert Boyle** studied the relationship between the **pressure p**
and the **volume V** of a confined gas held at a **constant temperature**.

Boyle observed that the product of the pressure and volume are observed to be nearly constant. The product of pressure and volume is exactly a constant for an ideal gas.

##
**p * V = Constant**

Thus, the law states that pressure(p) is inversely proportional to volume(V) or vice-versa.

This relationship between pressure and volume is called**Boyle's Law** in his honor.

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**Charles' Law**

Boyle observed that the product of the pressure and volume are observed to be nearly constant. The product of pressure and volume is exactly a constant for an ideal gas.

Thus, the law states that pressure(p) is inversely proportional to volume(V) or vice-versa.

This relationship between pressure and volume is called

The relationship between **temperature and volume**, at a **constant** number of moles and **pressure**,
is called **Charles and Gay-Lussac's Law** in honor of the two French scientists who first
investigated this relationship.

Charles did the original work, which was verified by Gay-Lussac. They observed that if the pressure is held constant, the volume V is equal to a constant times the temperature T.

##
**V = constant * T**

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## Avogadro's Law

Charles did the original work, which was verified by Gay-Lussac. They observed that if the pressure is held constant, the volume V is equal to a constant times the temperature T.

Avogadro's Law (Avogadro's theory; Avogadro's hypothesis) is a principle stated in 1811
by the Italian chemist **Amedeo Avogadro (1776-1856)** that

**
"Equal volumes of gases at the same temperature and pressure contain the same number of molecules regardless of their
chemical nature and physical properties".**

This number (Avogadro's number) is**6.022 X 10**^{23}.
It is the number of molecules of any gas present in a volume of **22.41 L** and is the same
for the lightest gas (hydrogen) as for a heavy gas such as carbon dioxide or bromine.

The law can be stated mathematically

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## Ideal Gas Law

This number (Avogadro's number) is

The law can be stated mathematically

The equation which gives the simultaneous effect of pressure and temperature on the
volume of a gas is known as an ideal gas equation or an equation of state for an ideal gas.

It can be derived by combining Boyle’s law, Charles’ law and Avogadro’s hypothesis as shown below:

where,

**n** = number of moles

**R** = universal gas constant = 8.3145 J/mol K

**N** = number of molecules

**k** = Boltzmann constant = 1.38066 x 10^{-23} J/K = 8.617385 x 10^{-5} eV/K

**k** = R/N_{A}

**N**_{A} = Avogadro's number = 6.0221 x 10^{23} /mol

## Implications of Ideal Gas Law

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It can be derived by combining Boyle’s law, Charles’ law and Avogadro’s hypothesis as shown below:

where,